1. Field of the Invention
This invention relates to the structural supports and, more specifically, to a lubricated sliding structure for supporting massive heat exchangers, and the like.
2. Description of the Prior Art
There is a need to support extremely large heat exchangers, pressure vessels and other devices in a manner that protects these structures from the effects of earthquakes as well as the structural shocks that may be caused by large, abrupt changes in pressure vessel temperature. This structural support, moreover, must be provided in a manner that permits adjustment to routine thermal expansion and contraction and affords a reasonable degree of access for inspection, maintenance and repair.
More specifically, in commercial nuclear power plants there is a need for large heat exchangers that may be forty feet in diameter and as tall as seventy feet, when erected. Because these heat exchangers operate at high temperatures, care must be taken to insure that the temperature of the concrete portions of the structure that support a heat exchanger of this size do not exceed 200.degree. F, or the concrete will lose its water for hydration or crystallization and ultimately turn into a powder. Because of the large structures that are involved, the effects of thermal expansion and contraction appear in these devices as size changes that are on the order of several inches. In view of these largescale effects, if the heat exchanger experiences a swift change in temperature through an accidental loss of one of the hot fluids within, it is believed that the device will thermally contract with sufficient speed to produce a massive, jarring impact with surrounding structures. In a similar manner, earth tremors and the like also might produce serious damage if the seismic forces are coupled to one of these large heat exchangers.
It has been suggested to secure a support plate to the lower end of the heat exchanger. The bottom of this plate is provided with a concave arcuate surface that rests upon a corresponding convex Lubrite plate, or other suitably lubricated bearing surface. Because the Lubrite plate would ultimately rest upon a concrete foundation, the downward vertical load imposed by the heat exchanger is absorbed in a manner that permits the structure to slide or to shift through small horizontal distances relative to the lubrite plate in order to safely accommodate some of the motions that are induced by these extraordinary forces.
The structure that characterizes this proposal, however, appears to raise the temperature of the concrete foundation to unacceptably high levels and also fails to provide some means for coping with upward vertical forces and horizontal forces that are of a substantial magnitude. Thus, there is a need for a heat exchanger support structure that keeps the foundation at an acceptable temperature while permitting the relative movement of the heat exchanger and support structure to slide through small distances in order to adjust to relatively minor dislocations, and also to absorb major horizontal and upward vertical forces that are caused by earthquakes, abrupt changes in heat exchanger temperature, and the like.